Mechanical metamaterials as an energy shield

Abstract

A metamaterial system for protecting a payload from external energy flux generated by an energy source includes a mechanical, metamaterial framework configured to circulate the external energy flux between the metamaterial system and the energy source.

What is claimed is: 
     
       1. A metamaterial system for protecting a payload from external energy flux generated by an energy source, wherein the external energy flux is a mechanical vibration, the metamaterial system comprising:
 a mechanical, metamaterial framework configured to circulate the external energy flux between the metamaterial system and the energy source, wherein the framework includes a unit cell having a plurality of outer inelastic elements pivotally coupled to one another at pivot points, wherein the plurality of outer inelastic elements define an outer periphery of the unit cell, wherein the framework additionally includes a plurality of inner inelastic elements, wherein each of the inner inelastic elements includes a first end coupled to one of the pivot points and a second end spaced inwardly from the one of the pivot points, wherein the framework additionally includes a first elastic element coupled to and extending between two of the pivot points, and a second elastic element coupled to and extending between two of the second ends, wherein the first elastic element extends parallel to the second elastic element. 
 
     
     
       2. The metamaterial system of  claim 1 , wherein the external energy flux is configured to be stored in the first and the second elastic elements and then released and returned back to the energy source. 
     
     
       3. The metamaterial system of  claim 2 , wherein each of the first and the second elastic elements includes at least one of a spring, a rubber band, or an elastic rod. 
     
     
       4. The metamaterial system of  claim 1 , wherein the plurality of outer inelastic elements include rigid bars. 
     
     
       5. The metamaterial system of  claim 1 , wherein the unit cell is one of a plurality of multiple unit cells that are assembled in an array. 
     
     
       6. The metamaterial system of  claim 1 , further comprising the payload, wherein the payload is coupled to the unit cell, wherein a state of the payload is independent from the external energy flux applied to the unit cell. 
     
     
       7. The metamaterial system of  claim 1 , wherein the unit cell has absolute zero stiffness. 
     
     
       8. The metamaterial system of  claim 1 , wherein isolation performance of the unit cell is adjustable in-situ according to a change of loading. 
     
     
       9. The metamaterial system of  claim 1 , further comprising the payload, wherein the payload is coupled to the unit cell, wherein the unit cell is configured to isolate vibrations in an ultra-low frequency band below 20 Hz for the payload. 
     
     
       10. The metamaterial system of  claim 1 , wherein the unit cell is configured to isolate vibrations in a full frequency band. 
     
     
       11. The metamaterial system of  claim 1 , further comprising the payload, wherein the payload is coupled to the unit cell, wherein the unit cell is configured to provide an energy shield for payload. 
     
     
       12. The metamaterial system of  claim 11 , wherein the unit cell is tunable based on the payload. 
     
     
       13. The metamaterial system of  claim 1 , wherein the elastic elements have adjustable positions. 
     
     
       14. The metamaterial system of  claim 1 , further comprising the payload, wherein the payload is disposed within the metamaterial framework. 
     
     
       15. The metamaterial system of  claim 1 , further comprising the payload, wherein the metamaterial framework is a first metamaterial framework, wherein the metamaterial system further includes a second metamaterial framework, and wherein the payload is disposed between the first and second metamaterial frameworks. 
     
     
       16. The metamaterial system of  claim 15 , wherein the first and second metamaterial frameworks are identical in size and shape. 
     
     
       17. The metamaterial system of  claim 1 , wherein the unit cell has a hexagonal outer shape. 
     
     
       18. The metamaterial system of  claim 17 , wherein the unit cell includes six outer inelastic elements forming the outer hexagonal shape, and wherein pivot points are disposed between the six outer inelastic elements. 
     
     
       19. The metamaterial system of  claim 18 , wherein the unit cell includes four inner inelastic elements. 
     
     
       20. The metamaterial system of  claim 19 , wherein the inner inelastic elements have lengths that are shorter than lengths of the six outer inelastic elements that form the outer hexagonal shape. 
     
     
       21. The metamaterial system of  claim 1 , wherein the first elastic element has a first spring constant and the second elastic element has a second, different spring constant.